Introduction

Cardiac catheterization is a diagnostic tool used to assess the extent of heart enlargement diseases. It is incredibly important to detect and diagnose heart enlargement as early as possible, as the chances of a positive prognosis increase greatly upon early intervention. Heart enlargement can be indicative of several other pathologies and its risk of development often goes hand in hand with other diseases or family history.¹

What is heart enlargement?

Medically termed cardiomegaly, heart enlargement is the dilation or swelling of the heart muscle and characterised as the most common type of cardiomyopathy (disease of the heart). Most commonly this disease is a manifestation of another disease and therefore considered a symptom rather than a condition itself. It may affect one or more chambers of the heart but is predominantly linked to swelling of the left ventricle (lower heart chamber).^1,2 

Heart enlargement is largely asymptomatic and therefore diagnosis can be difficult but if not treated, it can be deadly in periods of exertion. At rest, symptoms are often not present and are only experienced when stress is put on the heart, often through physical activity. 

Causes of heart enlargement

Causes of disease state can be classified into one of two categories: genetic or acquired factors. They usually result in damage to the heart or a condition that makes the heart work harder than usual. As the heart enlarges, it weakens and in most severe cases can cause heart failure and sudden death.¹

The main conditions associated with heart enlargement include existing heart conditions, metabolic disorders, hypertension and damage caused by a heart attack. In all cases, the heart cannot function properly due to the thickening or thinning of the heart walls or stiffening of the heart muscle, and thus sufficient beating is hindered. This primarily results in prolonged pressure or stress overload on the heart due to increased resistance within the periphery (surrounding arteries).³

The following conditions are associated with the development of heart enlargement:³

• Coronary artery disease (e.g. ischemia or myocardial infarction)
• Hypertension
• Congenital heart disorders (e.g. atrial septal defect)
• Pulmonary diseases
• Stenosis
• Infectious myocarditis (e.g. HIV)
• Cardiomyopathy (caused by toxins, familial, peripartum, idiopathic or autoimmunity)
• Infiltrative diseases (e.g. amyloidosis)
• Physiologic conditions (e.g. pregnancy, exercise-induced)
• Arrhythmias (e.g. atrial fibrillation)

Symptoms of heart enlargement

The main symptoms of cardiomegaly include:⁴ 

• Shortness of breath
• Fatigue 
• Edema (swelling in the legs or ankles)
• Dizziness
• Chest pain
• Palpitations with a heartbeat that is faster than normal or irregular 
• Low tolerance for physical exercise

Although these are symptoms related to heart enlargement, they are not indicative of a diagnosis and often the first notable symptom is unexpected heart failure or death. 

What is Cardiac Catheterization?

Cardiac catheterization is a procedure involving the insertion of a thin, flexible tube (catheter) into the blood vessels located in either the arm or groin. The tube is fed through the blood vessels to the heart where it is used for diagnostic and therapeutic purposes. It is predominantly used to assess heart functionality and provide access for the delivery of interventions. The procedure is carried out under local anaesthetic (area is numbed but the patient is awake), upon completion the catheter is removed, leaving only a small puncture wound that heals quickly.⁵ 

Types of Cardiac Catheterization

Diagnostic and interventional catheterization are the two major types of cardiac catheterization that can be used in either right heart or left heart monitoring. Right heart catheterization, otherwise known as a venous catheter procedure, is predominantly used to measure blood pressure levels within the right ventricle and pulmonary artery. Left heart catheterization, or an arterial catheter procedure, is used in the assessment of the left ventricle and aorta. Valves within the heart and blood circulation are assessed through the injection of a contrast medium (dye) through the tubing and subsequent viewing through X-ray imaging. In the case of heart enlargement, diagnostic cardiac catheterization examining all the above factors is essential in establishing risk.⁶  

Risks associated with Cardiac Catheterization 

This procedure is largely considered very safe, however, there are some associated risks. While uncommon, an allergy to the contrast medium is possible and therefore allergies need to be discussed before the procedure is performed. Localised bleeding at the catheter insertion point can happen but stops usually after a few days, if persistent or causes concern then you should contact your  GP. In very rare occasions, there is a minimal risk of serious complications involving damage to the blood vessels in which the catheter is inserted. This can be causal of a heart attack, kidney damage, stroke and in extremely rare instances, death.⁷ 

Role in assessing heart enlargement

While used in the overarching analysis of the heart muscle as a whole, cardiac catheterization can also give very accurate information on the extent of swelling in heart enlargement. The size of the heart chambers is determined through catherterization by measuring internal cardiac pressure, cardiac output and vascular resistance. In doing so, the overall risk of the condition can be considered. Blood circulation and pressure can assist in the identification of faulty valves, blockages or abnormalities within the blood vessels or chambers of the heart. These issues could be indicative of an underlying pathology which further down the line could be causative of heart enlargement. Determination of the underlying causes of the symptomology is essential in disease management.⁵ 

Echocardiography (cardiac ultrasound) and fluoroscopy (x-ray with dye) are used as imaging technologies within cardiac catheterization to assist in the diagnosis of the state of the disease. These images can be captured for referral at a later date. During the procedure it may be necessary to take a biopsy of any lesions or abnormalities, this can be facilitated by the insertion of instruments through the catheter to take samples.¹

Benefits of understanding heart enlargement

There are numerous benefits to understanding heart enlargement, namely the accuracy of diagnosis, monitoring, management and/or treatment. Accurate diagnosis is imperative to assuring the correct treatment can be administered, this may include dose, treatment or medication adjustments. The stage of cardiomegaly from moderate to severe may determine whether surgical intervention is required to prevent heart failure. As the condition worsens, monitoring is essential in case the course of treatment needs to change immediately. Determination of all these factors can assist in the enhancement of patient management and care to ensure that the disease state is controlled.^1,3,5

Summary

In the case of heart enlargement, it is crucial to understand the pathology comprehensively. Cardiac catheterization is a highly successful procedure in diagnosis and can be used to assess disease stages accurately. If this is not achieved timely, then the prognosis associated with heart enlargement can be bleak. Therefore, early detection and intervention are essential for heart health. Despite the invasiveness of this procedure, studies suggest that catheterization is the best course of action in this case.

Frequently Asked Questions (FAQs)

When should I see a healthcare professional?

You should seek medical advice if any of the symptoms above develop, particularly unexplained swelling, shortness of breath or chest pain, although these symptoms are not exclusive to heart enlargement. If you are at higher risk due to family history or lifestyle, it is important to attend regular checkups to allow for any changes to be noted and monitored periodically. Timely diagnosis is essential. 

How can I prevent an enlarged heart?

Prevention is often lifestyle related and implementation of these risk management strategies can significantly reduce risk. These include:¹

• A healthy diet
• Light exercise (for 30+ minutes)
• Healthy weight maintenance
• Healthy sleeping pattern (8 hours a night)
• Moderate alcohol consumption
• Stopping smoking 
• Managing cholesterol and blood pressure

What are the treatment options for heart enlargement?

Treatment can simply involve the management of symptoms through lifestyle changes as detailed above, others require medication. 

These include:¹

• Antiarrhythmics
• Diuretics
• Beta-blockers 
• Angiotensin-converting enzyme (ACE) inhibitors
• Anticoagulants

In severe disease states, surgical procedures may be required including:¹

• A pacemaker implant
• Bypass surgery of the coronary artery 
• Stent placement procedure
• Implantable cardioverter defibrillator (ICD) device placement 
• Replacement or repair of a damaged heart valve